The invention is related to a bearing unit, comprising a rolling element bearing, the bearing comprising at least two rings which are each provided with at least one raceway and at least one set of rolling elements which are in contact with the raceways, as well as at least one tubular sheet metal element connected to one of the rings.
Such a bearing unit is known, for instance from U.S. Pat. No. 3,860,301. The prior art bearing unit comprises sheet metal elements which are connected to each other. The sheet metal elements are carried out as bearing rings which enclose several rows of rolling elements.
The object of the invention is to provide sheet metal elements for the purpose of adding further mechanical features to the bearing unit, such as increasing the strength and/or stiffness of the bearing unit. Also, it is desirable to enable the transfer of forces and/or torques through such sheet metal elements.
The object is achieved in that the sheet metal element at least partly has a mounting part with non-circular cross section, the mounting part being mounted to a counter part with a correspondingly non-circular cross section of the ring or connected to the ring.
The non-circular part of the sheet metal element may serve several functions. First of all, it may provide additional stiffness to e.g. the bearing onto which it is connected. This may in particular be so in case the sheet metal element has e.g. a triangularly shaped cross section. Furthermore, the non-circular shape may provide a torque transfer means. In this connection, the counter part may comprise a cap connected to the inner ring.
According to the invention, the sheet metal element has a circular part which is opposite the inner surface of the inner ring, and a non-circular part which is tightly fitted within a correspondingly non-circular hollow part of the cap. Additionally, the circular part of the sheet metal element can be tightly fitted within the inner ring. Furthermore, the sheet metal element may have an end wall which closes one end of the tubular part. In that case, the cap and the end wall of the sheet metal element can be connected to each other through e.g. a screw/nut connection.
Furthermore, the sheet metal element may have an end wall which closes one end of the tubular part. In that case, the cap and the end wall of the sheet metal element can be connected to each other through e.g. a screw/nut connection.
The non-circular shape of the sheet metal element may take several forms; preferably, the cross section of the non-circular part can comprise e.g. three rectilinear wall sections which are angled with respect to each other.
In a further embodiment of the invention, the bearing unit according to the invention may be provided with a constant velocity joint which is connected to, or comprises, the tubular sheet metal element. As will be clear, the transfer of a driving torque to the rotating ring of the bearing plays an important role in this connection. Preferably therefore, the constant velocity joint has an axle stub provided with a noncircular cross section, the axle stub being tightly fitted within a correspondingly shaped space in the tubular sheet metal element. By means of the non-circular shapes of the axle stub of the constant velocity joint and of the sheet metal element, the torque transfer can be ascertained.
According to a particular embodiment, the axle stub has a shoulder onto which one end of the tubular sheet metal element bears. Also, the axle stub comprises a screw threaded bore and the end cap comprising aligned opening, the cap, sheet metal element and axle stub being drawn together by means of a screw accommodated in the opening and in the screw threaded bore.
According to a further alternative embodiment, the sheet metal element forms an integrated part of the constant velocity joint, the part being of non-circular cross section and being tightly fitted within a correspondingly non-circular hollow part of the cap.
For the fixation of joining of the several components addressed before, in particular the flanges of the cap and the flanges of the rings, several possibilities exist. These encompass mechanical means, such as riveting, energy welding, laser welding, spot welding or gluing. Also, cold rolling or orbital forming techniques can be applied to lock-up the rolling bearing section or to join the bearing parts. The materials used can be metallic or non-metallic. The latter case encompasses composite materials, powder materials or combinations of these. Of course, the joining or fixation depends on the materials applied.